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Circulatory System Flashcards

1
Q

what is the primary function of the circulatory system?

A

transport of O2/CO2, nutrients and metabolic waste

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2
Q

what are the secondary functions of the circulatory system? (2)

A

thermoregulation

transport of immune cells/hormones

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3
Q

what does the vascular system consist of? (2)

A

heart and blood vessels

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4
Q

what are the heart and blood vessels collectively referred as

A

blood vascular system

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5
Q

what are the two components to the circulatory system?

A

pulmonary circulation

systemic circulation

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6
Q

what is the flow of the pulmonary circulation?

A 
right atrium and ventricle 
pulmonary aa 
lungs 
pulmonary veins 
left atrium
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7
Q

what is the flow of the systemic circulation?

A

left atrium and ventricle
aorta
rest of body

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8
Q

passive drainage system for returning extravascular fluid (lymph) to blood and vascular system

A

lymph vascular system

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9
Q

what does the circulatory system lack?

A

intrinsic pump

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10
Q

what does the circulatory system rely on? (2)

A

muscle contraction

body movement

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11
Q

Blood vessels of circulatory system have common basic structure with three

A

tunics

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12
Q

tunics

A

concentric layers

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13
Q

innermost layer of simple squamous endothelial cells lining lumen

A

tunica intima

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14
Q

thickness of tunica intima

A

very thin, 1-2 cells thick

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15
Q

what does the tunica intima form?

A

a semi-permeable barrier, supported by a basement membrane

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16
Q

fascia occludens

A

specialized discontinuous tight junctions between endothelial cells

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17
Q

what kind of connective tissue does tunica intima contain?

A

variable amounts of sub endothelial connect tissue

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18
Q

Internal elastic lamina, if present, separates

A

tunica intima & media

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19
Q

what is the internal elastic lamina composed of?

A

elastic fibers

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20
Q

tunica media

A

highly variable middle layer

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21
Q

what is contained in the tunica media? (2)

A

smooth muscle cells and fibroblasts connective tissue

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22
Q

in arteries, the tunica media may also contain (2)

A

reticulin (type 3 collagen)

elastic fibers

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23
Q

where is external elastic lamina located?

A

between tunica media and adventitia

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24
Q

external elastic lamina compared to the internal elastic lamina

A

also composed of elastic fibers but less organized

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25
outermost layer
tunica adventitia
26
what kind of connective tissue is found in the tunica adventitia?
loose fibroblastic connective tissue
27
what types of structures are found in the tunica adventitia? (4)
fibroblasts collagen elastic fibers smooth muscle cells
28
is the tunica adventia thick or thin in arteries?
thinner
29
what is the thickest of the layers in venuoles?
tunica adventitia
30
what does the tunica adventitia contain in larger vessels?
vasa vasorum
31
what is contained in both large Aa and Vv?
small blood vessels that supply the tunica media and adventitia
32
tunica adventitia also contains autonomic nerves, called
nervi vasculares
33
what do Nervi vascular control?
smooth muscle contraction in vessel walls (vasoconstriction and vasodilation)
34
Vasoconstrictionof blood vessels due to action of
sympathetic, post-ganglionic nerve fibers
35
what does vasoconstriction on smooth Mm of tunica media to cause
a decrease in lumen diameter
36
what does it mean that vasoconstriction is passive?
occurs in the absence of inhibition of sympathetic stimulation
37
vasodilation is accomplished via
indirect parasympathetic innervation
38
how does acetylcholine act on edothelial cells?
causes the cells to release NO
39
what does NO cause
smooth muscle cells to relax
40
in response to low O2 tension, smooth muscle in the walls of arterioles
relax
41
relaxation of smooth muscle arterioles results in (2)
vasodilation | increase blood flow
42
two types of specialized sensory receptors located in walls of blood vessels
baroreceptors | chemoreceptors
43
baroreceptors detect
blood pressure
44
where are baroreceptors located? (2)
carotid sinus | aortic arch
45
chemoreceptors detect changes in (3)
CO2, CO2 tension | pH
46
where are chemoreceptors located? (2)
at bifurcation of carotid Aa | in aortic bodies of aortic arch
47
where does the arterial system conduct blood?
away from the heart, to the capillary bed
48
the venous system returns blood from
capillaries to the heart
49
cyclical pumping of heart
pulsatile blood blow
50
systole
contraction of ventricles | pressure wave
51
diastole
relaxation | decrease pressure
52
normal blood pressure
120/80 mm Hg
53
expansion and recoil of elastic arteries maintains
blood pressure
54
Regulation of bp accompanied by changes in
diameter of blood vessels
55
Regulation of bp accompanied by changes in diameter of blood vessels occurs via
sympathetic control of smooth Mm in vessel walls
56
Arteries contain large amounts of (2)
elastin & smooth Mm
57
arterial vessel wall diameter compared to lumen diameter
vessel wall thick relative to lumen diameter
58
elastic aa diameter
> 1 cm in diameter
59
elastic aa
large conducting vessels, receive blood directly from heart
60
elastic aa have sheets of elastic tissue in
tunica media
61
elastic tissue helps maintain bp between
systole and diastole
62
what do elastic aeries contain (2)
internal and external elastic laminae
63
diameter of muscular aa
~2-10 mm in diameter—medium-sized distributing Aa
64
muscular arteries have more --- and less --- than tunica media than elastic arteries
more smooth muscle | less elastin
65
what is the thickest later in muscular arteries?
the tunica media
66
muscular arteries have distinct
internal elastic lamina
67
larger muscular arteries may contain
external elastic lamina
68
diameter of arterioles
~10-100 um in diameter
69
arterioles contain relatively little
smooth Mm (tunica media only ~2-3 cells thick)
70
in arterioles, what is absent?
elastin laminae
71
arterioles are the terminal branches of the
arteriole system
72
what do arterioles supply?
capillary beds
73
what are arterioles a major site of? (2)
vasoconstriction | vasodilation
74
arterioles regulate distribution of blood to capillaries via
pre-capillary sphincters
75
pre-capillary sphincters
intermittent rings of smooth M within walls of arterioles
76
Metarterioles
small diameter arterioles; intermediate in size between arterioles & capillaries
77
what are metaarterioles characterized by
discontinuous layer of smooth Mm in tunica media
78
In general, amount of smooth Mm increase with
an increase in diameter of vessel (& relative amount of connective tissue decrease)
79
what is microcirculation is concerned with the exchange of? (5)
``` gases fluids nutrients metabolites waste products ```
80
where does microcirculation primarily occur within?
capillaries, also includes arterioles and venues
81
diameter of capillaries?
8-10 um, thin walled vessels
82
what are capillaries lined by?
a single layer of endothelial cells
83
what are capillaries supported by? (2)
basal lamina | small number of pericytes
84
Pericytes derived from same precursor cell as
endothelial cells
85
capillaries can differentiate into (2) following injury
endothelial cells or smooth Mm cells
86
what do capillaries lack? (2)
``` outer connective tissue layer (no tunica adventitia) smooth Mm (no tunica media) ```
87
what layer do capillaries contain?
tunica intima
88
do capillaries exhibit vasomotor activity?
Do not exhibit vasomotor activity themselves
89
Vasodilation & vasoconstriction accomplished via smooth Mm contraction in arterioles & pre-capillary sphincters, resulting in a
passive change in capillary diameter
90
continuous capillaries
endothelium forms continuous lining; most common (e.g., Mm, lung, CNS)
91
fenestrated capillaries
endothelial cells possess pores, or fenestraewithincells(e.g., endocrine glands, GI tract)
92
discontinuous
basal lamina not continuous; endothelial cells separated by large gaps between cells (e.g., liver, spleen, bone marrow, lnn)
93
Discontinuous capillaries may form
sinusoids (large diameter capillaries ~ 30-40 um)
94
Transport across capillaries may occur via (3)
fenestrae, transcytosis, or diapedesis

Histology (32 decks)

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